#include "string.hpp"
using std::cout;
using std::cin;
using std::endl;
namespace canoe
{
	void test_string()
	{
		//string s1;
		//std::cout << s1.c_str() << std::endl;
		string s("hello world");
		const string s1("");
		string s2(s);
		cin >> s;
		cout << s1 << endl;
		cout << s2 << endl;
		cout << s << endl;
		for (auto str : s)
		{
			cout << (str += 1);
		}
		cout << endl;
	}
}

int main()
{
	canoe::test_string();
	return 0;
}